ES2396363T3 - Procedure for the non-destructive test of a specimen by means of ultrasound as well as device for it - Google Patents

Abstract

Procedure for the non-destructive test of a test piece (100) by means of ultrasound, which comprises the following procedure steps: a. sound ultrasound pulses directed at the specimen (100) with a sound angle ß, electronically adjusting 5 the sound angle ß, b. record echo signals that result from the sonorized ultrasound pulses in the specimen (100), c. determine the ERS value ("equivalent reflector size"> = equivalent reflector size) of a defect (102) in the volume of the specimen from echo signals that can be assigned to the defect (102), for a multiplicity of angles of sound ß, by comparing the amplitude of the echo signals of the defect with echo signals of a reference defect as a model and d. generate a B-scan, a C-scan or a sector scan as a graphic representation of the defect (102), including this one at least qualitative representation of the dependence of the ERS values determined on the sound angle defect ß.

Description

Procedure for the non-destructive test of a specimen by means of ultrasound as well as device for it

The object of the present invention is a procedure for the non-destructive test of a specimen by means of ultrasound, in which in the context of the procedure an equivalent reflector size is determined for a defect found in the volume of the specimen from of the ultrasound echo signals that are recorded in the context of the procedure. Additionally, a device that is suitable for carrying out the process according to the invention is an object of the present invention.

Generic procedures are well known from the prior art. From US publication 2006/0219013 a non-destructive ultrasound test is known with a defect determination from echo signals for a multiplicity of sonorization angles and subsequent representation of the defect as a sector scan. A defect detected by means of an impulse-echo procedure, based on the sonorization of ultrasound pulsed in a specimen, in the volume of the specimen, for example a cavity, an inclusion or also a crack, is characterized by the indication of a value for its ERG equivalent reflector size (in English ERS “equivalent reflector size”). The value of this equivalent reflector size is determined by a comparison of the amplitude of the echo signals that come from the defect examined in the volume of the specimen, with a reference defect as a model of known size. In the so-called reference block procedure, the examiner compares the echo signals of the test specimen with echo signals that he obtains in a reference block equivalent to the test specimen, into which one or more reference reflectors are inserted. For this purpose, for example, cylindrical holes with known dimensions can be introduced into the reference block. The echo signals that are produced in an ultrasound reflection in the hole are then compared with the echo signals that are obtained in an examination of the specimen. In the case of the reference block procedure, the examiner therefore performs measurements both on the specimen to be examined and on the reference block prepared with a suitable probe, in which case it can be, for example, a probe suitable angular

On the contrary, in the case of the so-called AVG procedure, the amplitude of the echo signal resulting from a defect in the volume of the specimen is compared with an echo signal calculated theoretically and / or empirically determined from a reference defect as a model, which is generally adopted as a flat circular disk and is at the same depth in the specimen as the defect detected in the test performed on the specimen. To do this, a so-called AVG diagram is previously created for the probe used in the test, which includes the characteristics of the probe. The curves contained in the AVG diagram indicate the echo height that would generate a reference defect in a measurement with the probe used. In the case of a practical test objective, the examiner can then read the size of the equivalent reflector of the defect detected in the volume of the specimen by performing the acoustic attenuation correction (material specific acoustic attenuation) and the transfer correction (coupling losses test specimens) for the specimen directly from the AVG diagram.

In the case of a classical test procedure according to the AVG procedure, the examiner varies the position of the probe and the orientation with respect to the defect detected and attempts, thereby, to maximize the resulting echo signal. This process is designated, in the case of the material test by means of ultrasound, also "growth" of the ultrasound signal. The actual determination of the equivalent reflector size of the detected defect is then performed for maximized ultrasound echo.

Other details regarding the AVG procedure result, for example, from US patent document 5,511,425 A which originates from the previous holder of the requesting party. Additionally, the AVG procedure is described in detail in the book “Werkstoffprüfung mit Ultraschall”, J. Krautkrämer and H. Krautkrämer, 5th edition, Springer Verlag, ISBN 3-540-15754-9, chapter 19.1, pages 343-349. The technical details disclosed in this case with respect to the AVG procedure are added by this reference in a completely extensive manner to the declarative content of the present application.

The fact that, for a representative characterization of a defect in the volume of a specimen, an examination with a multiplicity of probes must be performed is disadvantageous in its currently extended form. This is based on the fact that for a given defect, a perpendicular sound in the specimen does not necessarily provide a maximum echo amplitude. Rather, it depends on the orientation of the defect in the volume of the specimen, at which sound angle a maximum echo signal can be obtained. To actually obtain a value of the equivalent reflector size of the detected defect that is reasonably correlated with the actual defect size, they are therefore used as a rule, in the context of standardized test procedures based on the AVG procedure, other angular probes that perform different angles of sound. This procedure means in practice a high test and documentation effort for the examiner, so that as a rule it is tested only in a few angles of sound. In addition, the variation of the sound angle requires a change of the probe, which causes additional problems due to the never-unique calibration at one hundred percent as well as the coupling properties of the probes. This also makes it difficult to interpret the ERS values detected in a defect.

Therefore, it is an object of the present invention to indicate a procedure for the non-destructive test of a specimen by means of ultrasound, which provides the examiner with a novel representation of a defect detected in the volume of the specimen. Additionally, a device that is suitable for carrying out the process according to the invention should be provided.

This objective is solved by a method with the characteristics of claim 1 as well as by a device with the characteristics of claim 14.

The method according to the invention according to claim 1 is provided for the non-destructive test of a specimen by means of ultrasound.

In the context of costly examinations it has been found that the ERS value of a defect often has a strong dependence on that angle at which the defect is sonorized. This angle is directly correlated with the sonorization angle 1, the angle at which the sonorized ultrasound is coupled to the specimen according to the procedure therein. In this regard, it has been found that the observed angular dependence of the ERS value of a defect allows conclusions to be drawn about the essential properties of a defect, such as its geometry as flat or bulky, particularly its symmetry.

In particular, it has been found that a classification of a defect detected in the volume of a specimen can be carried out by means of the angular dependence of its ERS signal. Correspondingly, it represents an essential simplification for the examiner, when he has a graphic representation of a defect that he has detected in the volume of the specimen, from which he can deduce the dependence of the ERS value on the sound angle defect. 1 at least qualitatively.

In an advantageous refinement of the method according to the invention, a modification of the position of the coupling site is detected during the procedure, in which ultrasound pulses used for the test in the specimen are sonorized. Such position detection offers, in particular, the advantage that position information can be used for the generation of a B-scan (X axis: position on the surface of the specimen, Y axis: depth on the specimen) or a C-scan of the specimen. In addition, position detection allows an especially effective measurement of the angular dependence of the ERS value of a defect.

In another preferred configuration of the process according to the invention, the influence of the electronic adjustment of the sound angle on the ERS value to be determined from the defect is automatically compensated with the calculation of the ERS value of the defect. Certain corresponding algorithms can simply be integrated into an activation unit for an ultrasound probe. Preferably, for the sonorization of the ultrasound pulses directed in the specimen an emission probe is used, whose ultrasound emitter comprises a multiplicity of independently activatable ultrasound transformers. For the electronic adjustment of the sound angle 1, the multiplicity of the ultrasonic transformers is then activated individually in a precise phase, so that the emission angle a of the ultrasonic emitter is varied. This results directly in a variation of the sound angle 1 in the specimen.

It is preferably provided in the context of the process according to the invention that, with the calculation of the ERS value of the defect that was detected in the volume of the specimen from the echo signals that can be assigned to the defect, it is automatically compensated computationally the influence of the electronic adjustment of the emission angle a and with it the sound angle 1 on the determined ERS value of the defect. The emission angle and the sound angle 1 can be considered as equivalent in the context of the present invention, since they are physically linked to each other in a fixed manner. In particular, this means that in the context of the process according to the invention, at least one of the following corrections is carried out automatically, however preferably several:

•

compensation of the modification of the size of the virtual ultrasound transformer or the opening of the ultrasound transformer connected therewith with the emission angle a or sound angle 1 that is modified,

•

compensation of the modification of the position of the coupling point of the ultrasound emitted by the ultrasound transformer in the specimen with the emission angle a or sound angle 1 that is modified,

•

 compensation for the modification of the acoustic wavelength path in the propagation body with the emission angle to which it is modified, and

•

compensation of the change of focus position in the specimen with the emission angle a or the sound angle 1 that is modified,

For the electronic adjustment of the sound angle 1, the phase matrix probes already mentioned have special advantages. However, this does not mean that, in the context of the process according to the invention, other ultrasound probes with a variable sound level could not be used with the precondition that the sound level can be adjusted electronically and can also be quantified.

In the context of the process according to the invention, at least one AVG diagram is advantageously used for the determination of the ERS value of a defect in the volume of the specimen from echo signals reflected by the defect. In this regard, this AVG diagram may be specific to the source of the ultrasound pulses, that is, particularly specific to the emission probe used. Additionally, the AVG diagram may be specific to the specimen material. In a first configuration, the AVG diagram additionally shows a dependency of the sonorization angle 1 of the ultrasound in the specimen or an equivalent angle size. In an alternative approach, the AVG diagram has no dependence on the sound angle 1, rather the influence of the sound angle 1 on the recorded acoustic amplitude or the ERS value of the defect in the context of the procedure is computed.

In the context of the test of the specimen, at least one calibration step is additionally covered. In this, the amplitude of an echo produced by a reference defect is detected. In the case of the reference defect, it is preferably a rear wall or a test hole of a test tube, and in the case of the rear wall echo, it is also possible to dispense with a separate test tube and the calibration stage can be performed directly on the test tube itself . Preferably, the calibration stage is performed for a multiplicity of sonorization angles and / or reference defects, however this is not mandatory.

The device suitable for carrying out the process according to the invention, which is dealt with even more precisely below, preferably offers in this respect the possibility for carrying out standardized calibration steps, in which it can be selected, for example, also with a multiplicity of pre-standardized adjusted specimens.

In a preferred configuration of the procedure, at least one of the following defect characteristics is represented in the graphic representation:

a) that sound angle 1, with which the ERS value of the defect is maximum, b) information on whether the ERS value of the defect is essentially constant at different angles of Loudness 1, or if it varies with different angles of sound.

Particularly, in the generated B-scan a defect detected by a bar can be symbolized, whose extension is correlated along its longitudinal axis with the ERS value of the detected defect. Advantageously, in this respect, the same scales are used for the representation of the ERS value and for the X-position on the surface of the specimen. The bar should be understood in the context of the present invention as an arbitrary geometric figure that is axially symmetrical with respect to two orthogonal axes with respect to each other, for example a line, a rectangle, an ellipse etc. In this regard, one of the two axes of symmetry of the bar is designated in relation to the present invention as its longitudinal axis.

To increase the interpretation capacity of the B-scan generated in the context of the process according to the invention, particularly to improve the intuitive detection capacity of the B-scan generated, it has been advantageous when the B-scan generated is adequately represented by the less one of the following additional characteristics of the defect detected:

a) the relative amplitude of the defect echo, b) the sound angle 1, with which the ERS value of the detected defect is maximum, for example the defect is represented as a bar that is perpendicular to the sound direction with which it results the maximum defect echo, c) the relative defect size, d) information about the echo acoustic wavelength path, for example the bifurcation from which the defect echo originates, and e) information on whether the ERS value of the detected defect is the same or different for all the sonorization angles 1 examined in the context of the predetermined defect limits.

The indication of relative values may, for example, refer to reference values measured in relation to the test of the specimen.

For this, one or more of the following indicator parameters can be used advantageously in the B-scan:

a) the color of the bar,

b) the dimension of the bar transversely to its longitudinal axis (width of bar B),

c) the angle of the longitudinal axis of the bar towards the surface of the specimen, and

d) the basic geometric shape of the bar.

As an example, some representation possibilities for various defect characteristics are explained in more detail below.

In the context of the present invention, the information on whether the ultrasound echo that comes from the defect in the volume of the specimen, that is the amplitude of the echo, exceeds a relative echo amplitude must be used with relative amplitude

certain predetermined threshold. A threshold of this type may refer, for example, to the amplitude of the echo of the measured defect compared to the amplitude of a reference defect. In particular, a threshold can then be indicated in "millimeters of ERS", for example the ERS must be greater than or equal to a registered limit of 2 millimeters or 5 millimeters as an example.

If, in the context of the process according to the invention, the sound angle 1 varies and that sound angle 1 is determined with which the ERS value of the defect is maximum, then a reference point for the orientation of the defect in the defect can be provided to the examiner. the volume of the specimen, the longitudinal axis of the bar representing the defect in the B-scan being inclined, with respect to the surface of the specimen. The bar is advantageously represented in this case so that its longitudinal axis is perpendicular to the acoustic axis of the sonorized ultrasound with that angle a for which the ERS value of the defect is maximum.

Other relevant information for the examiner and the documentation is whether the ERS value of the detected defect is above or below a predetermined recorded limit. Thus it is possible, for example, in the generated B-scan, to completely suppress the defect signals below a certain threshold. Alternatively, such defect signals can also be coded in color or can be represented as transparent bars, to indicate the distance from the recorded limit (for example in "mm of ERS" or dB). In particular, the last two representation variants offer the advantage that the examiner may indicate that although a defect in the volume of the specimen is present at the site examined, however it is small with respect to its ERS value, so It does not need to be documented due to the relevant test instructions.

Additionally, it may be interesting for the examiner to find out the information from which sound wavelength path, that is, for example "bifurcation" of the sonorized ultrasound radiation, results in the defect echo. This information is particularly interesting in the case of conducting a test on a test tube with flat parallel surfaces, since in this case there is often a situation where the defect is first detected by ultrasound radiation, after which this was reflected at least exceptionally on the back wall of the specimen. This information can be determined from the path time of the defect echo and can be plotted in the B-scan, for example by colored bar coding, for the examiner.

Additionally, it is important for the examiner to find out if the defect detected in the volume of the specimen is to be considered as an extended surface defect or as a three dimensionally extended defect. Three-dimensionally extended defects will generally be cavities or defects that are conditioned by manufacturing and often do not represent any risk for fatigue fractures. On the contrary, extended surface defects are generally correlated with cracks in the specimen, which can be symptoms of fatigue and have a strong tendency to spread, which can lead to fatigue fractures. A three dimensionally extended defect in the volume of the specimen is characterized in the context of the process according to the invention because the ERS value resulting from the defect is essentially independent of the sonorization angle. In contrast, two-dimensionally extended defects show a strong dependence on the sound angle. In this case, the information of whether it is a surface extended defect or a three-dimensional defect can be encoded in the represented bar. This can be done, for example, by adapting the length and width of the represented bar or also by selecting a geometric shape that represents the symmetry of the defect. However, a colored coding is also advantageously used on this site.

As an alternative to the previously described generation of a B-scan extensively, the generation of a C-scan can also be provided according to the invention (X axis: position in the x-direction on the surface of the specimen, axis

Y: position in the Y direction on the surface of the specimen) or the generation of a sector scan (also S-scan, X axis: distance from the sound / depth site in the test tube, Y axis: azimuthal angle: angle of loudness) and can be advantageous in special use cases. All the above embodiments for the representation of the defect characteristics determined in the B-scan can be transferred directly to the C and S sweeps provided further.

The process according to the invention allows to perform the AVG procedure reported in many test specifications now with modern ultrasound probes that allow an electronic adjustment of the sound angle in the specimen, for example using the phase matrix technique.

A device according to the invention according to claim 14 is provided for the non-destructive test of a specimen by means of ultrasound.

According to the invention, the ultrasonic emitter of the device has a multiplicity of independently activatable ultrasound transformers. Additionally, the activation and titration unit is configured to activate these ultrasound transformers individually in a precise phase so that the emission angle a of the ultrasonic emitter and thereby the sound angle 1 in the specimen can be adjusted electronically. Additionally, the activation and assessment unit is configured to determine, from the

echo signals that can be assigned to the defect, the ERS value of a defect in the volume of the specimen for a multiplicity of sonorization angles. Finally, the activation and evaluation unit is configured to generate a graphic representation of the aforementioned defect, from which the dependence of the determined ERS value of the sound angle 1 defect can be read at least qualitatively.

In particular, the generated graphic representation can reproduce the ERS value of the defect in direct dependence on the sound angle 1. From the angular dependence of the ERS value of the defect, the examiner (as discussed previously extensively) can draw conclusions about essential properties of the defect. According to the invention, the graphic representation generated of the defect is a B-scan, a C-scan or a section scan of the specimen, in which the ERS value dependent on the angle of the defect is properly recorded.

In a particularly preferred configuration of the device according to the invention, which is particularly advantageous in relation to the generation of a B-scan, C-scan or scan of sectors of the specimen, the device additionally comprises a path detection unit that is configured to detect a change in the position of the probe on the surface of the specimen. A trajectory detection unit of this type can be carried out, for example, by means of a mechanical path sensor that is arranged in the probe itself. However, path sensors that work optically according to the principle of the optical mouse can also be used. Finally, in case of the use of a matrix matrix ultrasonic emitter, the modifications of the ultrasound signals, which are produced in case of a modification of the position of the probe on the surface of the specimen, can also be consulted, for a determination of the position. The corresponding bibliographic citations have already been indicated. The use of a linear matrix allows, together with the detection of a modification of the position of the probe on the surface of the specimen in the direction of the longitudinal axis of the matrix, in addition to performing an electronic scan in this direction, activating successively different subgroups of transformers The use of a two-dimensional phase matrix particularly allows the detection of a modification of the position in two spatial directions, and also the detection of a rotation of the probe on the surface of the specimen.

With regard to the possibilities of reproducing essential defect properties in the graphic representations generated of the defect, it was already dealt with in detail in relation to the method according to the invention. The device according to the invention is preferably configured to generate the defect representations explained in relation to the procedure.

Finally, special advantages result when the activation and evaluation unit is configured to automatically compensate, with the calculation of the ERS value of the defect, the influence of the electronic adjustment of the sound angle 1 on the ERS value to be determined from the defect.

As already explained in relation to the process according to the invention, the ERS value of a defect can be determined, for example, in an automated manner by comparison with a multiplicity of stored reference values, and these values can be treated in case of reference, for example, of one or several AVG diagrams. In this context it is indicated that for the determination of an ERS value of a defect detected by means of the method according to the invention it must be available for each angle, with which the defect is audible, in addition to an AVG diagram also an echo of reference for example of a test tube.

In a particularly preferred configuration, a plurality of reference values are stored in the activation and titration unit, for example in the form of AVG diagrams that are correlated by groups with different sounding angles 1. In this respect, these reference values may be specific to the probe additionally. In particular, it can therefore be a number of specific AVG diagrams of the probe with respect to different sounding angles 1. Preferably, the probe is additionally provided with an electronic identifier that allows the activation unit to identify in case of connection of the probe of autonomously the type of probe or even the individual probe and select the specific reference values of the (type of) probe stored.

In all configurations, the determination of an ERS value (specific for the sound angle) for a detected defect requires, however, as a general rule that there is a reference value that was detected, for example, in a specimen with the respective angle, or proceed, however, from an interpolation between different measured angles.

Certain special advantages result when the activation and evaluation unit is configured to automatically compensate, with the calculation of the ERS value of the defect, the influence of the electronic adjustment of the sound angle 1 on the ERS value to be determined from the defect.

Thus, in an especially preferred configuration of the device according to the invention its activation and titration unit is configured to automatically convert from the emission angle to the ultrasonic emitter at the resulting sound angle 1 in the specimen, to compensate so automated the influence of the electronic adjustment of the sound angle 1 on the ERS value to be determined from the defect. In particular, this compensation can be configured specifically for the probe. In addition, it will be practically configured to take into account the specific ultrasound properties of the material of the propagation section and of the specimen such as, for example, the speed of sound.

Another improvement can be achieved when, for automatic compensation of the influence of the electronic adjustment of the sound angle 1 on the ERS value to be determined from the defect, the activation and evaluation unit of the device according to the invention is configured to compensate in an automated way the variation of the virtual ultrasound emitter size that is accompanied by the electronic variation of the sound angle 1 and with it the opening of the probe. The size of the virtual ultrasound emitter results from a projection of the actual geometric dimension of the ultrasound emitter in a perpendicular to the electronically adjusted emission direction of the ultrasound emitter. If the ultrasound emitter emits at an emission angle other than 0 °, then this directly results in a reduction in the size of the virtual ultrasound emitter. Since the size of the ultrasonic emitter is eventually included in the calculation of the ERS value of a detected defect, a corresponding automatic compensation must eventually be carried out.

Another improvement results when the activation and titration unit is configured to automatically compensate for the influence of the displacement of the coupling site X0, which is accompanied by an adjustment of the emission angle to or of the sounding angle 1, on the value of ERS that is going to Determine the defect.

Finally, an automatic compensation of the modification of the focus position in the specimen can be provided, which results in case of a variation in the emission angle a due to the modification resulting from the length of the acoustic wave path in the body of propagation.

Finally, it is indicated that the automatic compensation according to the invention of the influence of the electronic adjustment of the sound angle 1 on the ERS to be determined from the defect can be carried out based on AVG diagrams stored in two different ways. On the one hand, the activation and titration unit can be configured to normalize the actual measurement values (ie time-resolved echo signals) considering the influence of the setting of the sound angle 1, that is to say, for example, to convert the results of a conventional probe with fixed sound level 1. These are then adjusted with a normalized AVG diagram.

On the other hand, in the case of the creation of the AVG diagrams arranged in the activation and evaluation unit, the specific influences of the electronic angular adjustment probe on the echo signals can be considered, that is, in the stored AVG diagrams, the compensation to be made. This implementation must also be comprised by the method according to the invention as well as the device according to the invention.

Other advantages and features of the device according to the invention as well as of the method according to the invention result from the dependent claims as well as from the embodiments which are explained in more detail below by means of the drawing.

In this show:

Figure 1: a schematic representation of a device according to the invention for the non-destructive test of a specimen,

Figure 2a-2c: A scan-A of the specimen, recorded in different sound positions x as well as with

different sounding angles 1 as well as the amplitude path Amáx for an angle of

loudness 1 determined depending on the depth d in the specimen

Figure 3: a representation of the maximum echo amplitude Amáx depending on the sound angle 1,

Figure 4: A specific AVG diagram of the resolved angle probe,

Figure 5: a schematic representation of the radiation geometry in the probe,

Figure 6: a representation representing a B-scan of the specimen, in which a defect is represented by a respective ERS value, and

Figure 7: a representation corresponding to Figure 6 of the specimen with a multiplicity of defects that have different reflection properties,

Figure 8: a schematic representation of a procedure for the detection of the angular dependence of the ERS value of a defect in the volume of the specimen, and

Figure 9a, 9b: schematic representations of the ERS value dependent on the angle of two different defects in the volume of the specimen.

Figure 1 shows an embodiment of a device 1 according to the invention for the non-destructive test of a test tube 100 by means of ultrasound. The device 1 comprises an emission probe 10 which in turn comprises a propagation section 16 and an ultrasound emitter 12 disposed therein. In this regard, the ultrasound emitter 12 is arranged in the propagation section 16 so that in case of an excitation of the ultrasound emitter 12 for the emission of ultrasound pulses these are essentially coupled in the propagation section 16. The section Propagation 16 can be formed in this respect, for example, by a Plexiglas® body, as this is basically known from the state of the art. Preferably, the elements of the emission probe 10 are integrated in a common housing that is not shown in the figure for reasons of clear arrangement. In the case of the emission probe 10 shown, it is an angular probe that is intended to couple in the test tube 100 the ultrasound pulses emitted by the ultrasound emitter 12 with a sound angle 1 that is measured towards the surface normal of the input surface of the specimen 100. The use of angular probes is optional and not mandatory, and probes for perpendicular sonorization (ie 1 = 0 °) can also be used according to each case.

In the case of the ultrasonic emitter 12 used in the emission probe 10, it is an ultrasonic emitter of the phase matrix type, that is to say the ultrasonic emitter 12 comprises a multiplicity of ultrasound transformers 14 that at least form a linear arrangement and can be activated individually. The longitudinal axis of the at least linear matrix of the ultrasound transformers 14 is oriented, in this respect, in the direction marked X. By means of the directed adjustment of the phase position between the individual ultrasound transformers 14 it is possible to dynamically influence wide limits on the emission angle a, that is the direction of the radiation.

The emission probe 10 comprises in the exemplary embodiment shown a mechanical path detector 18 that mechanically samples the movement of the emission probe 10 on the surface of the specimen 100 and provides corresponding position information, for example in an activation unit 50 connected to the emission probe 10. Alternatively, the path detector 18 can also operate separately, for example according to the principle of the optical mouse. The trajectory detector 18 can preferably detect (regardless of its structural form) the movement of the emission probe 10 in two directions independent of each other on the surface of the specimen 100. Certain special advantages result when rotational movements of the emission probe can also be detected. 10 on the surface of the specimen. Based on the technology disclosed in US Patent Document 7,324,910 B2, as well as its improvement disclosed in German Patent Application Reference Number 10 2007 028 876.1 of June 26, 2007, a separately configured trajectory detector can be completely dispensed with, since all position information can be obtained from the signals of the ultrasound emitter itself 12.

An activation unit 50 is connected to the emission probe 10 which is configured to activate the ultrasound transformers 14 arranged in the ultrasound emitter 12 of the emission probe 10 individually in a precise phase manner. Additionally, the activation unit 50 is configured to join with an ultrasound receiver 40 to receive echo signals reflected back by a test tube 10, resulting from the ultrasound pulses sonorized by the ultrasound emitter 12. In the present example of embodiment shown, the ultrasonic emitter 12 arranged in the emission probe 10 also serves as the ultrasonic receiver 40. For this purpose the ultrasound transformers 14 contained in the ultrasonic emitter 12 are interconnected, configured separately and individually activated after the emission. of an emission pulse, electrically to an ultrasound emitter 12 with a large surface which then acts as an ultrasonic receiver 40. However, it is logically also possible to use a separately configured ultrasonic receiver 40 that can be arranged, for example, in a reception probe configured separately. A separate receiving probe of this type would also comprise in the present embodiment also a propagation section, corresponding to the propagation section 16 of the emission probe 10.

For the non-destructive test of a specimen 100 to determine hidden defects 102, for example, in the volume of the specimen 100 the emission probe 10 is joined with the control unit 50 and placed on the surface of the specimen 100. The Acoustic coupling of the emission probe 10 to the test tube 100 is generally carried out using a suitable coupling means, in which case it may be, for example, water, oil or also a water-based gel.

In the case of test tube 100, it is preferably a tool or mechanical part, however it can also be a biological sample.

Now the examiner moves the emission probe 10 along the direction marked X in Figure 1 on the surface of the specimen 100 from one part to another. At the same time, it observes the indication in an indicating device 52 assigned to the activation unit 50, which is integrated in the embodiment shown as a display in the activation unit 50. In the indicating device 52 it is represented in the embodiment example shown an image A, in which the amplitude of the ultrasound pulses reflected back to the given sounding site X is represented as a function of time. If the acoustic radiation emitted by the acoustic probe 10 encounters a defect 102 in the volume of the specimen 100, that is to say with a structure that reflects ultrasound such as a defect, a cavity or a crack, then a part of the sonorized acoustic radiation and returns in the same path to the ultrasonic emitter 12 of the emission probe. As mentioned, it acts at the same time as an ultrasonic receiver 40 that transforms the acoustic signal reflected back into an electrical signal that is then eventually amplified appropriately and emitted to the activation unit 50. In the activation unit 50, the received echo signal, which is generally found as an electrical signal, may be transmitted from the emission probe 10, however, however, for example, also in the form of an optical signal, processed in an appropriate manner, which can be done, for example, through highly analogue-digital conversion of resolved time and signal processing. The signal in the form of the A-scan described above in the indicating device 52 is shown below. If the sonorized ultrasound radiation encounters a defect 102, then echo signals resulting from this are directly visible in the A-scan. The procedure described above is advantageously carried out in this respect with the fixed sound angle 1.

If the examiner has detected a defect 102 in the method of procedure described above, then it attempts to maximize the amplitude of the resulting defect signal by varying the position X of the emission probe 10 on the surface of the specimen 100, ie Try to grow the signal. This signal growth is also carried out for a fixed sound level 1 1. The A-scan that results with the growth of the echo signal at different sounding sites X1, X2 and X3 are represented in Figure 2a. It is clarified that due to the modification of the path in the test tube 100, the echo signal is produced at different times, however it also varies in its maximum amplitude. This is because with the displacement of the emission probe 10 on the surface of the specimen 100, the center of the acoustic cone, in which the highest acoustic pressure prevails, moves over the defect 102. As a general rule, the amplitude results maximum in the echo signal when the acoustic radiation stumbles centrally with defect 102. If the amplitude of all echo signals is determined for a fixed sound level 1 1 in case of a variation of the sound site X, then it is obtained a representation of the echo amplitude as a function of the travel time or the depth of the defect 102 in the specimen 100, as this is graphically represented in the right diagram of Figure 2a. From this diagram you can determine the maximum echo amplitude Amáx (1 1), which results for the selected sound level 1 1.

Then, the examiner can vary the sound angle 1, so that he again performs the same examination for a modified sound angle 1 2. Alternatively, a modification of the automatic angle is also possible in the context of a partially automated test procedure. This also results in a diagram for the development of the amplitude as a function of the time or the depth of the defect 102 in the test tube 100. A diagram of this type is shown on the right in Figure 2b. The maximum echo amplitude resulting from this with the sound angle 1 2 does not necessarily correspond to the echo amplitude with the sound angle 1 1 chosen first, as a rule there will even be a deviation in this case, always that it is not a defect formed regularly.

If the different execution times, which result from the different sound angles 1 1 and 1 2, are compensated, then the peaks in the aforementioned representation of the amplitudes Amáx (1) are essentially in the same place D0. If, however, compensation for travel time of this type is dispensed with, then the peaks are found in different places.

By way of example, the result of the same procedure for a sound angle 1 3 modified again is shown in Figure 2c.

The sonorization angle 1 is electronically adjusted with the method of procedure described above using the advantageous emission properties of an ultrasonic emitter 12 of the phase matrix type.

In an alternative configuration, the activation unit 50 is configured to automatically optimize, for a given sonorization site X, an echo signal possibly resulting by varying the sonorization angle 1.

If the maximum amplitudes Amáx that result for different sounding angles 1 are applied over the corresponding sounding angle 1, then a diagram is obtained as is evident from Figure 3. From this diagram or the underlying echo data now that sound angle 1 can be determined for which the defect 102 examined shows the maximum echo amplitude Amáx. The angular dependence of the ultrasound reflectivity of the defect 102 can also be illustrated and analyzed in a simple manner. Of the possible interpretations of the behavior obtained with respect to the type of the defect 102, it was previously dealt with.

The so-called AVG diagrams are determined before the practical test explained above of the test piece (as is known from the state of the art for probes with fixed sound angle 1). In this regard, an AVG diagram shows the echo amplitude of circular disc reflectors of different diameters and also of an extended flat reflector (rear wall echo) as a function of distance, that is, as a function of depth d in the specimen . Unlike the AVG diagrams previously known for the state of the art and devices for ultrasound measurement, in which AVG specific diagrams of the probe are deposited, for example in digital form, are recorded or generated, in the context of the present invention, AVG diagrams

also with a resolved angle and eventually deposited in the activation unit 50. Figure 4 shows by way of example an AVG diagram of this type for a predetermined diameter of a circular disk reflector as a function of distance d and as a function of angle 1 .

For the determination of the ERS value of a defect with the aid of a phase matrix probe that allows an electronic variation of the sound angle 1 in the specimen 100, an adaptation of the general AVG diagram known by the prior art may be necessary (see US 5,511,425 A) which is based on theoretical considerations, in different respects. On the one hand, a calibration of the specific probe's AVG diagram is required in order to take into account the ultrasound properties of the specimen material and compensate for the specific effects of the probe such as a change of the ultrasound transformers or a modified probe coupling of emission in the test tube. To do this, before carrying out a real test of a test tube 100 in most of the test specifications, a calibration stage is required to calibrate the general AVG diagram that may already be deposited in device 1.

It must also be taken into account in the case of an electronic variation of the sound angle 1 with the aid of a phase matrix probe, that the ultrasonic properties of the probe are directly modified by the angle modification itself. For this reason the general AVG diagram, which was determined for a given sound angle, must be converted to another sound angle (electronically adjusted)

1. In particular, it is possible to perform this conversion on the device itself, so that it is not necessary to deposit a plurality of probe-specific AVG diagrams for different sounding angles 1. In an alternative approach it is logically also possible to deposit in device 1 a plurality of, for example, probe-specific ones that refer to a multiplicity of sound angles 1. Also in this case the AVG diagrams can be determined empirically or theoretically calculated.

As explained above, with the use of a device according to the invention, the sound angle 1 can be adjusted electronically. As is evident from Figure 5, it is modified, for example, in the case of an angular probe with a section of propagation with an electronic adjustment of the sound angle 1 both the coupling point of the acoustic radiation in the specimen in iX and the diameter of the acoustic radiation in its passage through the propagation section in the specimen. This can also be interpreted as a virtual modification of the dimensions of the ultrasonic emitter 12 (D D '), which must also be taken into account in the registration of the AVG diagrams mentioned above. By means of simple geometric considerations as well as the law of acoustic refraction it is possible to calculate in a simple way the influence of the electronic modification of the sound angle 1 on the modification of the coupling point and the size of the virtual ultrasonic emitter (12).

To now determine an ERS equivalent reflector size for the defect detected in the volume of the specimen, the examiner can represent (as with the devices previously known by the state of the art with probes with fixed sound angle 1) that AVG curve in the indicating device 52 of the activation unit 50 corresponding to the electronically adjusted sound angle 1, with which the maximum echo signal Amáx has been obtained. The AVG curve was calibrated, in this respect, before the actual measurement in reference defects that can be introduced, for example, in the specimen. In the case of "calibration" it is a calibration of the sensitivity of the probe used. As a general rule, the reference echo necessary for this is obtained from the rear wall echo in the so-called standardized "K1" or "K2" specimens (depending on the frequency of the probe used in each case). Since in these cases it is not a flat rear wall, a circular arc correction must still be performed (indicated by the probe manufacturer as a general rule). On the contrary, the reference reflectors of the component are rather scarce.

The AVG curve shown on the screen corresponds to a predetermined equivalent reflector size that as a rule corresponds to the registered limit predetermined by the test specification. If a defect is detected, whose echo exceeds the AVG curve represented on the screen, it is automatically indicated, for example, by the activation unit 50 (either in dB by the registered limit or directly in millimeters) the size of the ERS equivalent reflector obtained . In the AVG curve, the examiner can therefore directly read the size of the ERS equivalent reflector with the decrease of the pulse travel time towards the detected defect.

In an extensively automated test routine, the examiner performs a scan of the surface of the specimen 100 in the procedure mode described above, until it detects echo signals that from its point of view decrease by a defect 102 in the volume of the test tube 100. Eventually, in this case, a manual optimization of the defect signal is performed manually, before it changes the activation and titration unit 50 of the device 1 according to the invention to an automatic measurement mode. In this, the activation unit 50 activates the ultrasonic emitter 12 so that the coupling point of the acoustic radiation in the specimen is moved in the X direction on the surface of the specimen 100. At the same time, the activation unit 50 detects the amplitude of the resulting defect echo as a function of the coupling point and determines the maximum echo amplitude. In this respect, the sound angle 1 remains constant.

In a next procedure step, the activation unit 50 varies the sound angle, so that the defect 102 to be measured in the volume of the specimen 100 is sonorized with another angle 1 2. Also in this case, the unit of activation 50 the coupling point of the acoustic radiation emitted in the specimen varies by means of the appropriate activation of the ultrasonic emitter 12, at the same time detecting the resulting echo amplitude. Also in this case, the maximum echo amplitude Amáx (1 2) is determined with the sound angle set 1 2, that is, the examiner "makes" the echo signal grow.

By comparing with one or more specific AVG diagrams of the probe as well as the angle, the activation unit 50 of the device according to the invention then automatically determines the ERS value of the measured defect 102. For this, the activation unit 50 automatically compensates for the influence of the electronic variation of the emission angle a of the ultrasonic emitter 12 on the coupling point of the ultrasound radiation in the specimen and with it on the pulse travel time of ultrasound from the ultrasound emitter 12 to the defect 102. Additionally, the activation unit 50 also automatically compensates for the influence of the electronic variation of the emission angle a of the ultrasound emitter 12 on the size of the virtual emitter, such as described above. The activation unit 50 also automatically compensates for the modification of the focus position in the specimen by the modified sound wavelength path in the propagation body. Finally, the activation unit 50 automatically converts from the emission angle a into the sound angle 1, the material properties of the specimen being eventually considered as well.

In the result, an ERS value of the defect 102 detected in the volume of the test tube 100 is obtained, both from the test procedure carried out manually and in an automated way, and that sound angle 1, with which the signal is obtained. Max defect Max. Then, this data can be reproduced.

If there is additionally position information with respect to the probe, then the test result can also be represented in a B-scan, as it is reproduced by way of example in Figure 6, or also in a C-scan or a scan S way and mode graphics. Thus a bar of length L can be represented in the scan-B, whose position X on the surface of the specimen corresponds to that position X0 in which the defect is computationally. In the Y direction the bar is arranged in the depth Do corresponding to the computational depth of the defect in the volume of the specimen 100. Additionally, the length L of the bar representing the measured defect 102 is directly linked to the size of the reflector. ERS equivalent of the defect determined in the context of the test procedure according to the invention. Advantageously, the orientation of the bar is also directly correlated with that sound angle 1, in which the maximum echo signal Amáx is obtained. For this, the longitudinal axis of the bar with respect to the X axis can be represented inclined, so that the bar is oriented perpendicularly to the direction of propagation of the sound corresponding to that sound angle 1, with which the signal is obtained of maximum echo. The orientation of the bar in the B-scan shown in Figure 6 thus provides the examiner directly with information about the orientation of the defect measured in the specimen, which can also be reproduced and stored. In this regard, the B-scan schematically represented in FIG. 6 is shown to the examiner preferably in the same manner in the indicating device 52 that is connected to the activation unit 50. Preferably, the activation unit 50 is configured to transmit the stored data on a PC, where they can undergo an additional assessment.

Figure 7 finally shows another B-scan of a specimen 100, from which three defects 102 are evident in the volume of the specimen 100. The defects are, in this respect, in positions X1, X2 as well as X3. The defects 102 detected in positions X1 and X3 show, in this respect, a strong dependence on the echo signals of the sound angle, ie the variation of the maximum defect echo amplitude Amáx that results in case of a modification of the Sound angle 1 exceeds a certain threshold value. From this it can be concluded that these are defects 102 extended rather on the surface, correspondingly representing these defects in the B-scan of Figure 7 as essentially monodimensional symbols.

On the contrary, the defect 102 detected in position X2 shows an echo amplitude essentially independent of the sound angle 1, that is, the variation resulting from the echo amplitude remains below a predetermined threshold. From this it can be concluded in an extension of the rather uniform three-dimensional defect 102, which is represented in the B-scan of Figure 7 by a two-dimensional defect symbol (for example a circular disk as shown) whose diameter is correlated with the ERS equivalent reflector size of this defect.

By means of FIG. 8, a novel method is now illustrated which is also implemented in the device 1 according to the invention. In a first process step, the emission probe 10 is activated by the device 1 so that it sounds ultrasound pulses with a sound angle 1 fixed on the specimen

100. If the examiner has detected a defect 102 in the volume of the specimen 100, then it causes the defect signal to grow until the signal amplitude becomes maximum. In a next step the "sweep" function is activated, in which the probe 10 is activated by the device 1 so that the sound angle 1 in the specimen 100 is electronically varied within a predetermined range. The device 100 is further configured to then determine, from the received echo echoes with the different sounding angles 1, the maximum echo defect and the corresponding sounding angle 1 Max. If the position of the emission probe 10 on the surface of the specimen 100 is modified, then a sound angle results

modified 1, with which the signal echo is maximum, since a maximum defect echo is then obtained as a rule when the defect is detected centrally by ultrasound radiation. If an electronic angular scan is performed, as described above, then the device 1 can fully detect that modified sound angle 1, for which the defect echo becomes maximum. A variation of the position of the emission probe 10 on the surface of the specimen 100 can be determined by means of the procedure described above in an automated way the maximum defect echo for different sounding angles 1. In this respect the position of the probe can be performed of emission 10 on the surface of the specimen 100 on the one hand by a mechanical movement of the emission probe 10, however it can also be varied virtually by performing a linear scan within the plurality of individual ultrasound transformers 14 in the emitter of ultrasound 12 (called "electronic linear scanning").

If at least one AVG diagram is deposited in the apparatus, for example according to Figure 4, which for example may have been theoretically calculated or determined by means of practical measurements, then it can be determined from the defect echo amplitude diagram maximum determined for a given sound angle 1, the default ERS value for this angle. Eventually it may be necessary to calibrate the diagram / diagrams deposited in the device specifically of the probe or material by means of a reference echo obtained in a specimen, which is eventually recorded with different sounding angles, before it is performed the actual test of the test tube 100. The AVG procedure thus allows, in particular, the automatic compensation of the acoustic wavelength lengths that result for the different sounding angles in the test piece.

Alternatively, the device 1 may resort, in the case of the determination of the ERS value dependent on the angle of a defect 102 in the volume of the specimen 100, also to the position information provided by the path detection unit 18 As described above, the position of the emission probe 10 on the surface of the specimen 100 for which the amplitude of the defect echo is maximum is sought in a first stage for a fixed sound angle 1. A "plotting" function is then activated by the examiner in the device 1. If this is activated, the device 1 is configured to adjust, in a position that is modified from the emission probe 10 by means of suitable geometric calculations, that sound angle 1 in the emission probe 10, with which defect 102 is detected in the specimen centrally by ultrasound radiation also in the case of a modified emission probe position. In case of a displacement of the emission probe 10 on the surface of the specimen 100, the defect 102 always detected centrally by ultrasound radiation is then detected with the aid of the mentioned tracing function, so that the defect echo can be considered obtained as the maximum defect echo for the adjusted sound angle 1. Therefore, the maximum defect echo as a function of the sound angle can be recorded directly by varying the position of the emission probe 10 on the surface of the specimen 100 1 and from this the ERS value dependent on the angle of defect 102 can be determined as a function of angle 1.

Figures 9a and 9b finally show by way of example the development dependent on the angle of the ERS value of two different defects 102 in the volume of the specimen 100. In this regard, Figure 9a shows a defect 102, whose ERS value varies only weakly with the sound angle 1. Therefore it is apparently a defect 102 whose ultrasound reflectivity practically does not depend on that angle, with which the ultrasound radiation encounters the defect. Therefore, it can be assumed that the defect is widely isotropic at least with respect to that spatial direction, in which the position of the emission probe 10 in the examination mentioned above was varied.

Figure 9b shows, on the contrary, a defect whose ERS value depends very strongly on the sound angle 1. That is, the ultrasound reflectivity of defect 102 depends strongly on that angle, with which defect 102 is detected by ultrasound radiation At least with respect to that spatial direction, in which the emission probe moved to detect the dependence of the ERS value angle, the defect 102 to be classified as strongly anisotropic can be considered. Therefore, it can be, for example, a crack that is of mandatory registration with high probability, and therefore it must be properly graphically highlighted for example in a B-scan, C-scan or sector scan generated by the device 1, as explained earlier.

Claims (19)

1. Procedure for the non-destructive test of a test piece (100) by means of ultrasound, which comprises the following procedure steps:

to.

 sound ultrasound pulses directed at the specimen (100) with a sound angle 1, electronically adjusting the sound angle 1,

b.

 record echo signals resulting from the sonorized ultrasound pulses in the specimen (100),

C.

 determine the ERS value ("equivalent reflector size") of a defect (102) in the volume of the specimen from echo signals that can be assigned to the defect (102), for a multiplicity of angles of 1, by comparing the amplitude of the echo signals of the defect with echo signals of a reference defect as a model and

d.

 generate a B-scan, a C-scan or a sector scan as a graphic representation of the defect (102), including this one at least qualitative representation of the dependence of the determined ERS values on the sound angle defect 1.

2.

 Method according to claim 1, characterized in that a modification of the position of the coupling site is detected in which the ultrasound pulses are sonorized in the specimen.

3.

 Method according to claim 1, characterized in that the influence of the electronic adjustment of the sound angle 1 on the ERS value to be determined from the defect (102) is automatically compensated with the calculation of the ERS value of the defect (102).

Four.

 Method according to claim 1, characterized in that

to.

 for the sonorization of the directed ultrasound pulses an emission probe (10) is used, whose ultrasonic emitter (12) comprises a multiplicity of independently activatable ultrasound transformers (14), and

b.

 for the electronic adjustment of the sound angle 1, the multiplicity of ultrasound transformers (14) is activated individually in a precise phase, so that the emission angle a of the ultrasonic emitter (12) is varied.

5.

 Method according to claim 1, characterized in that at least one AVG diagram is used for the determination of the ERS value of the defect from the echo signals (AVG = distance, amplification, size (of the defect)).

6.

 Method according to claim 5, characterized in that the AVG diagram is specific for the source of the ultrasound pulses.

7.

 Method according to claim 5, characterized in that the AVG diagram has a dependency on the sound angle 1.

8.

 Method according to claim 5, characterized in that the AVG diagram is independent of the sound angle 1 and the influence of the sound angle 1 on the recorded echo amplitude is computed computationally.

9.

 Method according to claim 1, characterized in that, in the context of the test of the test piece (100), a calibration step is run at least once, in which the amplitude of an echo produced by a reference defect is detected.

10.

 Method according to claim 9, characterized in that in the case of the reference defect it is a rear wall or a test hole of a test tube.

eleven.

 Method according to claim 9, characterized in that the calibration step is performed for a multiplicity of sound angles 1.

12.

 Method according to claim 1, characterized in that the graphic representation of the defect (102) represents at least one of the following characteristics of the defect (102):

to.

 sound angle 1, with which the ERS value of the defect (102) is maximum,

b.

 information on whether the ERS value of the defect (102) is essentially constant for the different sounding angles 1.

13.

 Method according to claim 12, characterized in that

to.

 the defect (102) in the generated representation is represented as a bar, and

b.

 At least one of the following indicator parameters is used for coding the characteristics of the defect to be represented:

i. color, ii. angle of the longitudinal axis of the bar against the surface of the specimen (100), iii. Basic geometric shape of the bar.

14.

 Device (1) for the non-destructive test of a test tube (100) by means of ultrasound, with

to.

 an emission probe (10) with an ultrasonic emitter (12) that is configured to sound ultrasound pulses directed with a sound angle 1 in the test tube (100),

b.

 an ultrasound receiver (40) that is configured to record echo signals from the sonic ultrasound pulses in the test tube (100),

C.

 an activation and titration unit (50), which is configured to

i. activate the ultrasonic emitter (12) of the emission probe (10) so that the ultrasonic emitter (12) is excited for the emission of ultrasound pulses, ii. process the echo signals recorded by the ultrasound receiver (40), and iii. determine from the echo signals, which can be assigned to a defect (102) in the volume of the specimen (100), an ERS value ("equivalent reflector size" = equivalent reflector size) of the defect (102), in the one who

d.

The ultrasonic emitter (12) comprises a multiplicity of independently activatable ultrasound transformers (14), and

and.

 the activation and evaluation unit (50) is configured to:

i. activate the multiplicity of ultrasound transformers (14) individually in a precise phase, so that the emission angle a of the ultrasonic emitter (12) and thereby the sound angle 1 in the test tube (100) can be adjusted electronically, ii. determine from echo signals, which can be assigned to the defect (102), the ERS value of a defect (102) in the volume of the specimen for a multiplicity of sound angles 1 by comparing the amplitude of the signals echo of the defect with echo signals of a reference defect as a model, and generate a B-scan, C-scan or a sector scan as a graphic representation of the defect (102), including this one at least qualitative representation of the dependence of the determined ERS values on the sound angle defect 1.

fifteen.

 Device (1) according to claim 14, characterized in that the activation and titration unit (50) is configured to automatically compensate, with the calculation of the ERS value of the defect (102), the influence of the electronic adjustment of the sound angle 1 on the ERS value to be determined from the defect (102).

16.

 Device (1) according to claim 14, characterized in that the device additionally comprises a path detection unit (18) that is configured to detect a modification of the position of the probe (10) on the surface of the specimen (100).

17.

 Device (1) according to claim 14, characterized in that a defect is symbolized in the generated scan

(102) by a bar, the extension of which correlates along its longitudinal axis with the ERS value of the defect (102). 18. Device (1) according to claim 14, characterized in that the generated scan represents at least one of the following additional characteristics of a defect (102):

to.

 relative amplitude of the defect echo,

b.

 sound angle 1, with which the ERS value of the defect (102) is maximum,

C.

 relative defect size,

d.

 bifurcation, from which the defect echo proceeds, and

and.

 information on whether the ERS value of the defect (102) is essentially constant at different sounding angles 1.

19. Device (1) according to claim 18, characterized in that at least one of the following indicator parameters is used for coding the additional defect characteristics to be represented:

to.

 color,

b.

 dimension of the bar transversely to its longitudinal axis,

C.

 angle of the longitudinal axis of the bar towards the surface of the specimen,

d.

 Basic geometric shape of the bar.